WASHINGTON (AP) — Solar power is coming to President Barack Obama's house. The most famous residence in America, which has already boosted its green credentials by planting a garden, plans to install solar panels atop the White House's living quarters. The solar panels are to be installed by spring 2011, and will heat water for the first family and supply some electricity. Energy Secretary Steven Chu announced the plans Tuesday in Washington at a conference of local, state, academic and nonprofit leaders aimed at identifying how the federal government can improve its environmental performance. Former Presidents Jimmy Carter and George W. Bush both tapped the sun during their days in the White House. Carter in the late 1970s spent $30,000 on a solar water-heating system for West Wing offices. Bush's solar systems powered a maintenance building and some of the mansion, and heated water for the pool. Obama, who has championed renewable energy, has been under increasing pressure by the solar industry and environmental activists to lead by example by installing solar at 1600 Pennsylvania Avenue, something White House officials said has been under consideration since he first took office. The decision perhaps has more import now after legislation to reduce global warming pollution died in the Senate, despite the White House's support. Obama has vowed to try again on a smaller scale. Last month, global warming activists with 350.org carried one of Carter's solar panels — which were removed in 1986 — from Unity College in Maine to Washington to urge Obama to put solar panels on his roof. It was part of a global campaign to persuade world leaders to install solar on their homes. After a meeting with White House officials, they left Washington without a commitment. Bill McKibben, the founder of the 350.org group, said Tuesday the administration did the right thing. "If it has anything like the effect of the White House garden, it could be a trigger for a wave of solar installations across the country and around the world," McKibben said in a statement. What was unclear Tuesday was how much the White House solar project will cost, and how much fossil fuel-based electricity it would displace, since the system is not yet designed and the White House will not disclose how much energy is needed to keep the president's lights turned on. Based on available roof space, administration officials expect the photovoltaic system will include between 25 to 75 panels and will convert sunlight into 19,700 kilowatt hours of electricity a year. That would save a typical household $2,300 on its electricity bill, based on commercial rates in Washington. The solar hot water heating system, based on government estimates, could save an additional $1,000 a year. But the White House is far from a typical house, noted Danny Kennedy, the founder of California-based solar energy provider Sungevity, which offered to put solar panels on the White House for free earlier this year as part of a campaign called SolarontheWhiteHouse. Kennedy estimates that outfitting Obama's pad with solar would cost about $100,000 if paid out of pocket. But the money would be earned back with savings on the electric bill in the first five years, he said in an interview from the Maldives, where he is installing 48 solar panels on President Mohammed Nasheed's private residence. Kennedy said his calculations were based on a 5,000 square-foot California home, which uses 60,000 kilowatt hours of electricity annually. "They use a lot more electricity than that," Kennedy said. "We had to make a few assumptions about what electricity cost was in the White House."